-LRB- CNN -RRB- -- The United Nations has launched humanitarian plans worth $ 1.5 billion to help ease the suffering of millions of Syrians both inside and outside the country .

More than 525,000 Syrians have already crossed into neighboring countries , the United Nations announced Wednesday , and it estimated that more than a million will flee in the next six months .

The body believes that a quarter of Syria 's population needs food , shelter , medical attention , hygiene materials , clothes and other relief after enduring nearly two years of war .

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The United Nations is also asking for more than $ 520 million in additional aid , anticipating that the situation will only get worse in 2013 .

That amount , officials believe , will help contribute to aid for an estimated 4 million people inside Syria who urgently need help . The number of residents suffering has quadrupled from 1 million in March 2012 to 4 million in December , the United Nations reported Wednesday .

Many have fled . Between 2,000 and 3,000 refugees are crossing into Turkey , Jordan , Lebanon and Iraq every day , according to the United Nations .

Plans to help Syria have changed much over the past several months , which is `` indicative of the rapid developments on the ground and the dramatically deteriorating humanitarian situation in the country , '' said Radhouane Nouicer , the regional humanitarian coordinator for Syria with the United Nations . `` The magnitude of this humanitarian crisis is indisputable . ''

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The aid announcement comes on the same day that one of the United Nations ' outreach groups told reporters that about 100,000 Palestinians have fled a large refugee camp in the Syrian capital of Damascus due to government airstrikes and fighting there .

By daybreak Wednesday , 1,092 refugees from the Yarmouk camp had crossed into Lebanon through the Masnaa border crossing , seeking refuge with relatives in Palestinian camps in Bekaa , Sidon and Beirut .

Yamouk camp spokesman Abu Mohammed , who supports the Free Syrian Army 's cause of unseating President Bashar al-Assad , told CNN that the Palestinian people at the camp are not fighting in the war .

`` The camp was supposed to be a safe haven , '' he said . `` This was created as a safe zone for refugees . No one can find anywhere else to go . ''

He said non-stop shelling on the Yarmouk camp has forced tens of thousands to flee , but Mohammed estimates 100,000 remain . `` You have 100,000 people trapped under mortar shelling surrounded by a large Syrian Army presence . This could be a true massacre , '' he said .

He called on the international community for help .

But a Palestinian politician whose group is believed to support Assad said the Free Syrian Army and its affiliates are responsible for injecting the refugees into the conflict .

`` The Yarmouk camp was safe business as usual until the last few weeks , when the FSA started shelling the camp from outside , '' said Hussam Arafat , of the Popular Front for the Liberation of Palestine General Command . `` They were clashing and firing mortars on the Syrian army , which was based on the outskirts of the camp ... Then they managed to control the camp after a bloody battle with the Syrian army . ''

Life is dangerous even for the elite in Syria these days . Interior Minister Mohammed Shaar was admitted to the American University Hospital in Beirut on Wednesday for treatment for injuries sustained when his ministry building was bombed last week , the official Lebanese news agency NNA reported Wednesday .

`` Minister Shaar is in a stable condition , sustaining burns and shrapnel and will not need surgery ... He needs observation and treatment , '' one of the doctors who treated Shaar told NNA .

Other Wednesday developments

At least 161 people were killed across Syria Wednesday , according to the Local Coordination Committees of Syria , a Syria-based opposition activist network . Of those deaths , 67 occurred in Damascus and its suburbs , and 50 occurred in Aleppo .

At least 40 people were killed and dozens were wounded by a car bomb that exploded in Aleppo 's Marjeh neighborhood , the LCC said .

The Damascus suburb of Deir Al-Asafir endured fierce shelling from rocket launchers , according to the LCC .

The FSA downed a war plane in Hama , the LCC said

In Homs , Assad 's forces raided university residences near Shamas village and arrested students , the LCC said .

CNN 's Ivan Watson in Istanbul , Salma Abdelaziz in Atlanta , and Kareem Khadder in Jerusalem contributed to this report .

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NEW : At least 161 people killed across Syria Wednesday , according to rebel group

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United Nations : A quarter of Syria 's population needs food , water , shelter , medical care

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The U.N. is seeking more than $ 520 million in additional aid saying things are likely to worse

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Syria has been in the midst of war since March 2011 that pits rebels against al-Assad 's forces